1. Field of the Invention
The present invention relates to a slide fastener and more particularly to a fastener stringer having a row of successively interconnected coupling element scoops woven into a longitudinal edge of a stringer tape during the weaving thereof by a needle loom.
2. Prior Art
Slide fastener stringers of the type described are generally divided into two categories, one comprising a coiled plastic monofilament woven into a longitudinal edge of a woven stringer tape as the tape is woven, and the other comprising a preformed coupling element assembly which is woven into a longitudinal tape edge during the course of weaving of a stringer tape, the coupling element assembly consisting of a row of discrete coupling elements interconnected by embedded connecting threads.
The first-mentioned stringers have been proven less useful on articles that are expected to meet severe pulling tension.
The second known stringer employ connecting threads having a smooth surface that fails to provide a required degree of bonding strength so that interconnected coupling elements are liable to be accidentally displaced from a proper positional relationship with each other. Another problem with the stringer is that the connecting threads, which are made rigid enough for secure attachment of the coupling elements to a stringer tape, are not stretchable sufficiently to allow for smooth engagement and disengagement between opposed rows of coupling elements.
U.S. Pat. No. 3,328,857, issued July 4, 1967 to Burbank discloses another and somewhat more successful stringer comprising a series of spaced individual coupling elements connected by a pair of cords, one along each side of the stringer and having secured thereto the legs of the coupling element. Alternate sections of each cord in the spaces between coupling elements are covered with plastic, with those sections on one side of fastener being staggered with respect to the covered sections on the cord on the other side of the fastener, to thereby seek to provide the stringer with a desired degree of flexibility. However, the cord covered with plastic serves to reinforce the plastic sections and makes the coupling element row less flexible.